Revert of skstd -> std for unique_ptr (patchset #17 id:320001 of https://codereview.chromium.org/1436033003/ )

Reason for revert:
Chromium bots can't handle forward declared types, e.g.

struct Foo {
   int x,y;
   std::unique_ptr<Foo> next;
};

https://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_asan_rel_ng/builds/86497

Original issue's description:
> skstd -> std for unique_ptr
>
> TBR=reed@google.com
> No public API changes.
>
> BUG=skia:4564
>
> Committed: https://skia.googlesource.com/skia/+/755c553c17b82bb5de3d9cc8d3b2a866ff9e9e50
>
> CQ_EXTRA_TRYBOTS=client.skia.compile:Build-Mac10.9-Clang-x86_64-Release-CMake-Trybot,Build-Ubuntu-GCC-x86_64-Debug-CrOS_Link-Trybot;client.skia:Perf-Mac10.9-Clang-MacMini6.2-CPU-AVX-x86_64-Release-Trybot,Test-iOS-Clang-iPad4-GPU-SGX554-Arm7-Release-Trybot
>
> Committed: https://skia.googlesource.com/skia/+/06189155d987db5c7e69015f6ea87c2168d6a065
>
> Committed: https://skia.googlesource.com/skia/+/70e8dfca4a7f5bce97b8021a6e378c4828b09c8c
>
> Committed: https://skia.googlesource.com/skia/+/dadfc245cc9a0279ff7b73da3344f2ca5d139907

TBR=bungeman@google.com,mtklein@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:4564

Review URL: https://codereview.chromium.org/1498583002

1 files changed, 3 insertions, 6 deletions

diff --git a/include/core/SkRefCnt.h b/include/core/SkRefCnt.h
index abe3fb2827..0e8d857722 100644
--- a/include/core/SkRefCnt.h
+++ b/include/core/SkRefCnt.h
@@ -9,8 +9,8 @@
 #define SkRefCnt_DEFINED
 
 #include "../private/SkAtomics.h"
+#include "../private/SkUniquePtr.h"
 #include "SkTypes.h"
-#include <memory>
 
 /** \class SkRefCntBase
 
@@ -185,15 +185,12 @@ template <typename T> struct SkTUnref {
 /**
  *  Utility class that simply unref's its argument in the destructor.
  */
-template <typename T> class SkAutoTUnref : public std::unique_ptr<T, SkTUnref<T>> {
+template <typename T> class SkAutoTUnref : public skstd::unique_ptr<T, SkTUnref<T>> {
 public:
-    explicit SkAutoTUnref(T* obj = nullptr) : std::unique_ptr<T, SkTUnref<T>>(obj) {}
+    explicit SkAutoTUnref(T* obj = nullptr) : skstd::unique_ptr<T, SkTUnref<T>>(obj) {}
 
     T* detach() { return this->release(); }
     operator T*() const { return this->get(); }
-
-    // unique_ptr's operator bool() is not always be explicit on Android.  Make sure this is.
-    explicit operator bool() const { return this->get() != nullptr; }
 };
 // Can't use the #define trick below to guard a bare SkAutoTUnref(...) because it's templated. :(